In the leaching of ores, particularly of gold bearing ores, several desired metals, including gold, are extracted (leached) simultaneously using sodium cyanide as a leaching material Other metals which may be present in addition to gold are silver, palladium, platinum, cobalt, copper, iron and nickel. It is common practice to melt the metals in the leachates into a common precious metals bar which is then refined at a metals refinery. Leachates of gold ores may contain small amounts of platinum and palladium. The expense of recovering such small amounts of these materials from the precious metals bar is very high.
It would be desirable to have a process in which the leachates could be treated to preferentially remove platinum and palladium. Such a process would be particularly advantageous where the platinum and palladium content of the leachates is very small compared to the gold content.